Hemodynamics related to the progression and regression of atherosclerosis will be studied in M. fascicularis monkeys. Non-invasive and invasive techniques will be used to evaluate and quantitate the severity of atherosclerosis in terms of altered arterial pulse wave velocity and distensibility. Correlations will be made with changes in anatomical morphology, angiochemistry, and biophysical properties of the arterial wall. These studies should provide a link between the physiology and pathology of atherosclerosis and should provide a basis for non-invasive evaluation of early atherosclerosis in humans. Pulsatile hemodynamics related to graded degrees of arterial stenosis in dog carotid and femoral arteries also will be studied. Non-invasive measurements of blood velocity with Doppler ultrasound proximal and distal to the stenosis will be evaluated using computer frequency analysis technique. Measurements also will be made of pulsatile blood pressure and flow and related specifically to the severity and location of the stenosis. These studies should provide information useful in non-invasively detecting and evaluating stenotic atherosclerosis in human patients as well as in our non-human primate models of atherosclerosis.